During the production of semiconductor devices it is often necessary to precisely locate and align the semiconductor components so that they can be tested, burned-in and/or permanently attached in the correct spot. For example, semiconductor devices often have many, closely spaced electrical contacts which may be in the form of pads, conductive bumps, or the like. If the device is to be electrically tested, or stressed (burned-in), the device must be precisely aligned to a test fixture or test probe so that the contacts on the device match up with the contacts on the fixture or probe. For the same reasons, the semiconductor device must be precisely aligned during final assembly into a package.
Conventionally alignment has been accomplished with vision guided placement systems. These vision guided placement systems use cameras to capture digital pictures of the semiconductor devices and, in some cases, the substrate to which the semiconductor device is to be mated. A computerized system then compares, matches and aligns the semiconductor device to the substrate. These vision guided placement systems have the disadvantage of being costly and relatively slow. Also, they do not provide any way of keeping the semiconductor component aligned once it is in place. Consequently, any later movement can create misalignment.
An additional method of aligning a semiconductor component involves physically constraining the outside edges of the component by placing the component between raised perimeter edges sized larger than the component, either randomly within the opening of the raised perimeter edges or forced into a chosen corner with springs. FIG. 1A shows a semiconductor component 2 randomly placed in a fixture 4. This method relies on the edges of the fixture 4 for aligning the semiconductor device 2. These edges are usually formed by cutting, casting or molding techniques, making it difficult and expensive to precisely align a semiconductor component with this method.
Referring now to FIG. 1B, in order to partially overcome these limitations a spring 5 is sometimes used to force the semiconductor component 6 into a desired corner of the semiconductor fixture 8. This is an improvement over randomly placing the semiconductor component in the fixture. However, the dimensions of the semiconductor device 6 and the fixture 8 must still be extremely precise in order to achieve precise alignment of the semiconductor component with this method.
An alternate approach uses three point edges 9 to align a semiconductor component when pushed into the desired corner by the spring. See FIG. 1C. This method also relies on the precision of the dimensions of the device and the fixture features 9, in order to achieve precise alignment. Again, because these edges are made using standard forming techniques it is difficult to achieve a precise alignment.
Consequently it is desirable to have a method that precisely aligns a semiconductor component which does not require a slow and expensive visual guided placement system or require precise edges on the semiconductor component and fixture or other aligning surface.